PRICES: Sushi and sashimi $25--$35 for full dinner (plus tip, tax, beverages). Prix-fixe omakase sushi or sashimi arrays are $27 (to feed one fully). Special dinners can go much higher. Some sakes are very steep.

CUISINE AND BEVERAGES: Pristine, sea-fresh, creative sushi and sashimi in the pure Japanese style. (Menu of cooked Japanese dishes is less interesting.) Large selection of sakes.

NEED TO KNOW: In the corner of a mini-mall marked with a 7-Eleven sign on the east side of the street (easiest approach from the south), opposite Rubio's. Crowded parking lot, but spots open quickly. Don't bother with Americanized "party rolls" (e.g., California Roll, or any roll with cream cheese!), but watch other diners to spot off-menu extravaganzas. Expansion into new second dining room (with door to/from parking lot) makes wheelchair access possible, although space is still tight. Very loud when crowded. Reservations essential (you may still have to wait for a table). Call one month ahead for Ota-San's own counter station. Quality is best late in the week (Wednesday or Thursday--Saturday) when Ota is present. Call ahead to order takeout.

The sensei (a vigorous, youthful-looking man in his 50s) is chatting with student Jim after a swordsmanship class. "You must go eat at Sushi Ota," says Shima Sensei. "I know Ota personally, he is the most professional sushi chef here. You know, when people visit San Diego from Japan, that is where they eat. When nihonjin eat there, they get completely different food from gaijin."

"In what way different?" Jim asks.

"My favorite dish there is lobster sashimi. The back half is chopped-up raw lobster meat. The front half is still moving. Shows that the meat is really fresh."

Jim (aside): "My people are such savages..."

Cut to: Split-screen, Jim and Naomi at their computers a few miles apart.

Jim emails Naomi his conversation with Shima Sensei and Naomi realizes there's an amazing learning opportunity here, a chance to discover whether or not the long-standing rumor is true that at Ota, Japanese patrons get very different food from Americans. (Cut to the chase.)

Fade In: A table at Sushi Ota, in the new back room that has expanded the premises.

Jim's mother Masako has joined us to serve as translator, if necessary. She is a tiny, dainty-featured live wire with shoulder-length black hair and four-inch heels that raise her height to about 4'9". Shima Sensei is wearing a Hawaiian shirt, signifying relaxation mode, a side of his strict teacher that Jim has never encountered before. Naomi is secretly nervous -- will she seem like a foreign savage? Masako and Shima confer over the drink list, speaking in Japanese, and order a bottle of sake, Toko Yama ("Man's Mountain"), a strong, smooth blend with a flavor reminiscent of Thailand's Mekong brand rice-based whisky. Naomi orders her usual half-bottle of Nigori, "Japanese fizzy water," unfiltered sake with the texture of a milkshake -- baby-food sake, but reliably palatable.

On the table is a plastic-laminated half-sheet with photos displaying three omakase menus (one for sushi, two for sashimi). This is relatively new and very welcome. With sashimi, the center of your extravaganza can either be lobster or aji, Spanish mackerel. The two isseis discuss the issue of "omakase." "It means, 'I trust you, please take care of me and feed me whatever you want,'" says Shima Sensei. These arrays are the equivalent of impersonal prix-fixe tasting menus. "If you want an omakase dinner made just for you," says Masako, "it's best to find a sushi chef you like and trust, and go regularly, always sitting at his station, until he learns your tastes. At that point, he can do a true omakase for you. For instance, that chef will know better than to give me some disgusting roll with cream cheese. I like little rolls with small rice, I don't like fat rolls with big rice. He'll know that."

Choosing a chef to trust is another important issue. "I will only eat sushi from chefs who are trained in Japan," says Shima Sensei. "There, it is a very long and disciplined education, like martial arts...."

Flashback: Naomi, ten years younger, in San Francisco at the counter of the neighborhood sushi restaurant (one of the best in the city). A journeyman sushi chef is meticulously assembling a caterpillar roll as he responds to her question.

Chef: "First you work as an apprentice, 10 or 12 years before you become even a journeyman and are allowed to make sushi and sashimi. First few years, you only make rice, learn all about rice -- the differences in brands, how old it is, where it was grown, because you will cook and season it a little differently depending on those things. This is why at some American sushi bars the rice is not right -- too soft, too hard, with too much or too little sushi-su, the sweet rice vinegar for seasoning. When you understand rice, then they let you touch fish -- more years learning to handle fish, cut fish, and then how to judge its quality and buy it. When a Japanese sushi apprentice finally qualifies as a journeyman, it means his fish should be safe to eat. Then he can work at a sushi counter until the itamae [the master chef] tells him that he has learned enough to be a master chef himself." Chef inserts two radish sprouts into the head of the hilariously realistic-looking "caterpillar" and hands it over the counter to Naomi, who oohs and aahs and giggles at the little vegetable-sprig "palps."